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05 Stealth Gray V
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Re: camaro flex disc install help!

Creative Steel will rent you this tool.

The camaro disc would have to be better than the revshift part. IMHO and as far as I know, I haven't seen any confirmable reports from any reliable sources that the revshift part will work unless your driveshaft is perfectly straight and perfectly aligned with the output flange of the transmission. The reason it doesn't seem to work that well is because none of use have perfectly aligned driveshafts and at least mine wasn't perfectly straight either although it was very very close. The output flange "fingers" didn't seem to be perfectly straight with each other either based on checking the runout of the output flange with a dial indicator...close, but not quite. Because none of this is perfect, the disc has to flex at least a little to make up for these imperfections and the revshift part, as far as I'm concerned, is to hard to flex as we need it too. As the factory V1 disc ages, it gets pretty cooked and thus starts loosing its ability to flex and the more out of line your driveshaft is, the more the disc will need to flex.

This will all be magnified by motor and transmission mounts that may change driveshaft angles as they sag with age or from replacements that are slightly taller or shorter than the factory mounts are designed to be. The UMIs I previously had in the car were not great in this regard and I was glad to get rid of them.

The camaro part seems to be working well in my car but if I ever see a need to take the car that far apart again, I will be trying to modify a camaro disc to work 100% in the V1. I'll do this by taking it to a machinist I use for work and blackmailing him into at least trying to either machine down the collar or drill it/cut it out and press in a new insert/collar. We'll see but for now, the camaro disc it is....
 

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05 Stealth Gray V
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Re: Flex Disc / Drive shaft Coupler Camaro part number

I just received mine today and ordered it off GM parts direct part#92249108. Mine only came with 3 bolts, nuts and two of the washers fell out of the box. Did the rest of yalls come with 6 or 3 bolts? Do you have suggestions on replacement ones at a local auto store? would rather use Hex head vs the star bolts sent.
Mine only came with 3 so I just reused the old ones....
 

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'05 CTS-V
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Re: Flex Disc / Drive shaft Coupler Camaro part number

I'm going to be installing a voodoochikin improved driveshaft in the near future, so I was looking around online to see about replacing the flex disk while I've got things apart. Since the Camaro part isn't quite a direct fit, I did some more looking around. Rockauto.com lists a Dorman part number that isn't correct - they (Dorman) show the same parts for the V6 and CTS-V, but the driveshafts are different, as are the flex disks. On ls1tech, Revshift posted a couple years ago that they had bought the Dorman part and compared it to a stocker and it's not right.

In searching around I stumbled across this ad on Ebay for an SGF (German company) flex disk for $95. The listing shows they've sold some, but I don't believe I've seen anyone post about these here or on ls1tech. I looked at their website (which is towards the bottom of the Ebay listing) and they list the flex disk separately there for ~$25 more than the Ebay listing. Of note, their web site shows 3 CTS driveshaft options (looking at a 2005 CTS) - V6 manual, V6 automatic, and CTS-V manual - as they should. Unlike the Dorman part, these guys show a different flex disk part number for the CTS-V, which strikes me as a good sign, since we know the parts are actually different.

I took the part number from their ad and went looking for that elsewhere online. WIPGAP01-003 doesn't come up with anything, but GAP01-003 does - www.powertrainindustries.com shows that as the flex disk that comes with their 3694-221 driveshaft assembly for our cars. OK, good, now I have 2 separate sites listing that as the correct flex disk. Interestingly enough, that part number also comes up as the flex disk for the '03-10 Porsche Cayenne / VW Touaeoeueareg ;); Rockauto.com shows Dorman 935-107 for that application for ~$95.

Even better, if I search for SGF GAP01-003 on Amazon, I find it for only $79. That's $15-20 cheaper than the OEM Camaro part that started this thread, which seems like a pretty good deal to me.
 

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'05 CTS-V
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Re: Flex Disc / Drive shaft Coupler Camaro part number

I went ahead and ordered the SGF part (GAP01-003) from that Amazon listing. I don't think I'll be doing the driveshaft replacement until the 2nd weekend in October, so it'll be a little while before I have confirmation that the part is correct, but I don't expect to have any issues.
 

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I received the SGF part today (ordered on Friday from Amazon, received on Monday, free shipping - booyah!). Dimensions and markings seem to match up perfectly with details for the OEM flex disk posted by another member over on ls1tech. I won't actually get around to installing it for another couple weeks, but it seems that SGF GAP01-003 is legit.
 

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Back in October I installed my new SGF flex disk, but I never updated this thread. I learned something new today about how the flex disk is supposed to be installed, which reminded me of this thread. I'm going to have to get under my car to check out the flex disk, because I didn't even know to look for this when I did the install a while back.

The install was relatively straightforward. My old one didn't appear to be in terrible shape - I've seen some that were heavily cracked and degraded, whereas mine looked OK. However, the rubber had definitely been worked over the years such that once it was unbolted it was no longer flat / straight:



My new coupler doesn't have the Porsche / VW part numbers on it. However, comparing the old vs new side-by-side, you can see the markings all match up, and the Porsche / VW part numbers have clearly been ground off the new one - you can see the little scuffed rectangles where the part numbers used to be. I've seen that on other plastic and rubber aftermarket parts I've bought over the years. I'm guessing it's a contractual thing, that the automakers don't allow the parts manufacturers to sell OEM parts, so the part manufacturers just delete the OEM part numbers for legal reasons.



As for the new piece of information I learned today... On the side of the flex disk there are molded-in arrows at each bolt hole. Those arrows must be pointing towards the flange at each bolt hole in order to ensure the flex disk is oriented properly. I just assumed the thing was symmetrical, but according to this diagram from SGF, the structure inside the rubber is actually not symmetrical - it alternates thick and thin between the pairs of bolt holes:



If you install the disk rotate one hole off, the thick and thin structures won't be oriented correctly. This picture borrowed from Bavarian Autosport shows what the arrows look like:



You can see those same arrows on the "bent" old flex disk in my picture above. I vaguely recall seeing those on the side of the flex disk, but I didn't realize that they meant anything, so I have no idea if I aligned them properly.

Edit: Not quite as interesting a discovery as I thought. The extended sleeves that the bolts pass through mate up with the tranny and driveshaft flanges, so that ensures that the arrows are pointing the right direction. You'd have to bolt it up with the sleeves not engaging the flanges to get it wrong, and that would be pretty obviously wrong.
 

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2013 XTS
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So I'm getting some minor vibrations more at higher speed. I thought about just ordering stock replacement parts and taking my driveshaft in to be balanced. I have slight mods and don't track it. Would anyone suggest this or go down different path?
 

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2017 ATS-V M6 Sedan; 2005 CTS-V (gone. Drove the crap out of it while I had it)
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Discussion Starter · #28 ·
First off, there is technically no stock replacement number for the flexdisc. There are a couple of options discussed here: the GM Camaro part and an SGF part.

When I changed my flexdisc (to the Camaro part), I had 81k miles on the car. I did a bunch of work all at the same time because (a) it needed to be done and (b) the drive shaft was coming out anyway. So, all at once I did:

* Engine mounts (Creative Steel)
* Transmission mount (Creative Steel)
* Flexdisc (GM Camaro part)
* Diff bushing (Creative Steel)
* Diff block (Creative Steel)
* Gforce Axles to get rid of the wheel hop

It all works together fine. You might want to check the other soft bits in the drivetrain -- especially the trans mount since that can help to wear out the flexdisc.
 

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So I'm getting some minor vibrations more at higher speed. I thought about just ordering stock replacement parts and taking my driveshaft in to be balanced. I have slight mods and don't track it. Would anyone suggest this or go down different path?
Whether I would take a different path depends on what you have already checked and/or eliminated. Statistically, most high speed vibration issues are tire, or wheel related - tire wear, balancing, bent wheel, etc. Additionally, the V can develop high speed vibrations particular to 6th gear (or on rare occasion 5th gear) due to a known transmission issue. Finally, there are potential vibration issues with the axle CV joints. Assuming all that has been eliminated, the path you discuss is probably what I would do. I am however, bias toward the stock driveshaft and related components.
 

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Just came across this thread: I'm going to have my tranny out soon and thought it might be a good idea to replace the flex disk since the car is 10 years old, has 160k and I suspect, like others, that the rubber is pretty hard at this point due to age and heat. What is the consensus guys - I have the part numbers for the Camaro option and the SGF - which one seems like the better option? And dumb question: I assume GM doesn't have a direct flex disk replacement for our cars, hence this whole thread/exploration of legitimate OEM replacements?

----------

I checked out the SGF one on Amazon - that one seems like about as close a direct OEM replacement as we're gonna get if GM/Cadillac really doesn't offer a direct replacement anymore. SGF says they make these flex disk couplers for Cadillac too. Any reason I shouldn't pull the trigger on this?
 

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2013 XTS
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Whether I would take a different path depends on what you have already checked and/or eliminated. Statistically, most high speed vibration issues are tire, or wheel related - tire wear, balancing, bent wheel, etc. Additionally, the V can develop high speed vibrations particular to 6th gear (or on rare occasion 5th gear) due to a known transmission issue. Finally, there are potential vibration issues with the axle CV joints. Assuming all that has been eliminated, the path you discuss is probably what I would do. I am however, bias toward the stock driveshaft and related components.
Well, I have rev shift motor mounts, rev shift rear diff bushing, rev shift trans insert. I have no idea how to check the transmission- it shifts fine (I have the ls7 clutch now). I'm good with aftermarket components, but stock is also OK.
 

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Well, I have rev shift motor mounts, rev shift rear diff bushing, rev shift trans insert. I have no idea how to check the transmission- it shifts fine (I have the ls7 clutch now). I'm good with aftermarket components, but stock is also OK.
Attached is general information regarding diagnosing vibration.

Balancing your driveshaft is unlikely to do any harm, but it may, or may not address your vibration issue.

Looking at the list of your existing modifications, there are two that can introduce vibration. One is the LS7 clutch, which can introduce vibration unless the pressure plate and clutch disc were balanced as a package before installation. This source of vibration, an unbalanced LS7 clutch, reportedly diminishes over time.

Another potential source of vibration is the Revshift transmission insert. This is not because there is anything wrong with the Revshift insert, but rather because the driveline alignment in the CTS-V has a narrow range "tolerance." Based on numerous reports on this forum, replacement transmission mounts are a crap shoot - some transmission mount replacements/inserts work with certain motor mounts in terms of vibration, but not with others. This sometimes necessitates some trial and error with transmission mounts/inserts. (The stock transmission mount is expensive.)

If either of the two modifications are the cause of your vibration, you would likely know it because the vibration would have showed up coincident with the change.
 

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2006 CTS-V
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I did the voodoo service, new factory flex (amazon), cs trans mount. I am now getting drive shaft vibes around the 55mph mark (coasting or on the gas). I also have revshift mm and cs trans bushing and block. Voodoo says to "try shimming carrier down with washers just a bit to resolve any alignment issues". Anyone have this experience? And did you get it resolved?
 

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Yes, you can put the 3 bolts for testing alignment coming from trans through the coupler direct into the 3 holes from the driveshaft flange and then look after fasten them together, where the gap is, put 1 washer on mine every side and it's complete on driver's side, so much, the bolt holes of bearing bracket allow me to go!

Did you have balanced your driveshaft after changing the middle bearing?

Regards
Ronald
 
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